Preparation Of Large PBA Latex Particles By Agglomeration And Study On Toughening Effect Of ASA Resin

ASA resin(acrylate-styrene-acrylonitrile terpolymer)is a typical rubber-toughened polymer alloy,in which the size of rubber phase greatly affects the toughness of resin.Agglomeration that the latex particles with a small size are stably agglomerated into the latex particles with a large size by physical or chemical means can quickly enlarge the size of latex particles so that it can meet the demand of industrial production of ASA resins to improve the toughness of ASA resins.At present,the latex particles prepared by agglomeration methods still have the disadvantages such as existing many primary particles and poor storage stability.The main objective of this work is to prepare large size latex particles with wide size range,controllable size distribution and excellent storage stability,a new agglomeration method was developed and its application in the preparation of ASA resins was studied.Herein,the poly(butyl acrylate)(PBA)latex particles with the mean sizes ranging from 150 to 700 nm and size distributions ranging from 0.15 to 0.35 were prepared by the reation agglomeration of functional groups between P(BA-co-AA)and P(BA-co-DMAEMA)latexes which were prepared based on emulsion polymerization.The content of BA and DMAEMA monomer,amount of agglomeration agent,agglomeration temperature,stirring rate,agglomeration time and electrolyte amount on the agglomeration process were systematically investigated.The chemical composition,average size,size distribution,Zeta potential,surface tension,storage stability and morphology of the latex particles before and after the agglomeration were tested by infrared spectroscopy,laser particle size analyzer and scanning electron microscopy,respectively.The study results showed that the introduction of functional monomers reduces the stability of latex system to a certain extent,and the agglomeration process can be driven by the salification reaction between functional groups on the agglomerated particles and the agglomeration agent particles.The increase of the content of functional monomers in the agglomeration and agglomerated latex particles can significantly increase the effect of the agglomeration,and the lower stirring rate(100 rpm)can improve the monodispersity of the latex particles after the agglomeration.Adding the electrolyte with appropriate content can improve the effect of the agglomeration,but the stability of PBA latex system decreases,and then prolonging the agglomeration time can improve the monodispersity and stability of the PBA latexes.Finally,the agglomerated PBA latexes have good storage satibility.PBSA composite particles were synthesized by graft copolymerization using the agglomerated PBA latex particles,styrene,and acrylonitrile.ASA resin was further prepared by blending the PBSA composite particles with SAN resins(styrene-acrylonitrile copolymer).The effects of rubber content,rubber particle size,size distribution and core-shell ratio in PBSA composite particles on mechanical properties of ASA blending materials were studied.The tensile property,thermal stability and glass transition temperature,and fracture surface morphology of ASA blending samples were characterized by notched impact testing machine,electronic universal testing machine,thermal weight loss analyzer,differential scanning calorimetry,and scanning electron microscopy,respectively.The content,size and size discribution of rubber particles and the core-shell ratio of PBSA particles have great influences on the properties of the ASA materials.When the sizes of rubber particles are about 200～400 nm,the size discribution of rubber particles is 0.2,the content of rubber is 15 wt%,and the core-shell ratio of PBSA particles is 3:2.5,the ASA material has good toughness.Generally,the agglomeration method developed in this study has an important application prospect in preparation of the ASA resin.